In my lifetime, our planet has lost about half its coral reefs. From dynamite fishing to coastal pollution, predator invasions and lethal marine heat waves...these ecosystems are retreating everywhere after thriving for millions of years. Today, we know that the chemicals in our sunscreens are an additional source of pollution on popular reefs around the world. But what if something as simple as making the switch to healthy sun protection could take some pressure off the world’s most endangered ecosystems?

This year, the state of Hawaii was first in history to ban the sale of sunscreens containing oxybenzone and octinoxate to protect its coral reefs, providing countless goods and services to the people of Hawaii. This new law wasn’t received well by manufacturers, and here is why: these chemicals are used in 97% of sunscreens and 70% of cosmetics on the market as UV-filters. In other words, most personal care products seating on your bathroom shelf may contain oxybenzone (aka benzophenone-3) and/or octinoxate. So what lead Hawaii into making such a controversial ban? Since the start of my investigation I have become more and more clueless on the reasons why these compounds were approved in skincare formulations in the first place...

In case you didn’t know, oxybenzone and octinoxate are characterized as “Hazardous to the aquatic environment, long-term hazard » by the United Nations Global Harmonized System (GHS). As they leach off the skin – in the shower or swimming in the ocean – these compounds wash off into various water sources with insidious consequences on aquatic and marine life.

UV-FILTERS ARE TRAVELLING UP THE FOOD CHAINOxybenzone and octinoxate are ubiquitous environmental contaminants and are found in streams, rivers, and lakes and in marine environments from the Arctic Circle (Barrow, Alaska) to the beaches and coral reefs along the equator [1-7]. They can be found in swimming pools and hot tubs, and even in our drinking water (municipal treated and desalinated sources).

Oxybenzone and octinoxate may also bio-accumulate and be biomagnified in organisms [8, 9]. Biomagnification means they may increase in concentration in the tissues of organisms as it travels up the food chain. A number of aquatic and marine species have been discovered to be contaminated, from carp, catfish, eel, white fish, trout, barb, chub, perch and mussels to coral, mahi-mahi, dolphins, sea turtle eggs, and migratory bird eggs [10, 11]. Finally, additional testings have revealed oxybenzone also acts as an endocrine disruptor on marine invertebrates such as shrimps and bivalves [12]. Other ingredients commonly found in cosmetics – such as butylparaben, octocrylene and a chemical called 4MBC – have proven highly toxic to marine life. You can find the full list at www.haereticus-lab.org.

ARE THEY THAT BAD FOR CORALS? YES.These compounds eventually disperse in oceanic currents, accumulate in sediments or are absorbed by organisms where they can have devastating effects on invertebrates especially on juvenile development stages [13]. Downs et al. (2015) quantified impacts at the scale of coral fragments and coral polyps, showing death at certain concentrations within the conditions of an experimental tank. Laboratory testing showed that exposure to oxybenzone can inhibit and alter the growth of baby corals, is toxic to seven coral species and is likely to induce coral bleaching in the wild [13].

Exposure to oxybenzone or octinoxate causes a healthy coral fragment (left) to bleach within 14 days (right) at concentrations starting from 1 part per billion (octinoxate) and 500 part per trillion (oxybenzone). Source: haereticus-lab.org

Oxybenzone and octinoxate both induce coral bleaching and DNA damage at concentrations starting from one drop worth in an area the size of six and half Olympic swimming pools [13]. That means that in highly touristic areas – particularly in heavily frequented, closed systems such as coves - sunscreen pollution should be addressed as an environmental hazard. Meanwhile, sunscreen manufacturers require “sound scientific evidence proving that, under naturally occurring conditions, sunscreen ingredients are contributing to coral-reef decline”. Scientists have however seen a clear effect on highly frequented – and contaminated - reefs in Maui and claim it is enough evidence to justify a ban [13].

What I think? Considering the critical state of coral reefs worldwide, applying the precautionary principle by promoting chemical-free and other mineral-based sunscreens on highly frequented coral reefs and coastal areas would take some pressure off these fragile ecosystems in decline. Besides, by switching to mineral sunscreens we will also be doing a favor to our skins and personal health. We don’t mention enough the skin and health impacts reported from exposure to these two ingredients in cosmetics. This will change in my next blog ;-)

DID YOU KNOW?

Oxybenzone is used in 70% of cosmetic products as a UV-filter

Even a drop of oxybenzone in an ocean area the size of six-and-a-half Olympic swimming pools can damage corals. Researchers found concentrations 12 times that rate in popular waters off Hawaii.

Oxybenzone can be detected in urine within 30 minutes of application. If you live in a town near a coral reef and without a sophisticated sewage treatment, flushing the toilet or washing off sunscreen in the shower will impact reefs nearby.

Long gone is the time when we covered ourselves in mud or olive oil to protect our skin from UV-rays. Today, sunscreens are made in the lab and available everywhere at any price and texture. The down side is? Whether you pick the cheap 5L tub or a fancy mist recommended by your pharmacist, you are probably exposing your skin to loads of nasties...

​In my twenties, I had absolutely no idea [and no care] what my sunscreen contained, as long as I didn’t get a burn... What’s more, I considered sunscreen an unpleasant thing and I wouldn’t put much thought into choosing one for me. As summer came around, I would go to the store and get it over with: pick the highest SPF at the lowest price. What I didn't know was that my life as a marine biologist would have me involved with sunscreens more than I could ever have imagined! But that will be the topic of another blog. This one is about helping you understand sunscreens and giving you what it takes to make an informed decision on your next purchase.

To act as required, sunblocks must contain some type of UV-filter that absorb, reflect or scatter UV light. Listed as ‘active ingredients’ on your tube, these filters are either of chemical or mineral origin (sometimes, both are used together in one formula). Formulators then achieve desired texture by adding varying qualities of anti-microbial preservatives, moisturizers and anti-oxidants, which are labeled ‘inactive ingredients’ and account for up to 70% of the product.​Oxybenzone (aka benzophenone-3 or BP-3), benzophenone-4 (BP-4), para-aminobenzoic acid (PABA) and PABA esters, cinnamates, salicylates, camphor derivatives, dibenzoylmethanes and anthranilates [2]... The list of chemical UV-filters is awfully long and unfamiliar. What’s more, they are generally used in combination because no single one, at currently permitted concentration, provides sufficient protection against UV radiation...Hello chemical cocktail!!

That was enough to raise my suspicions on a product I apply on my skin everyday. I started browsing the scientific literature and soon discovered that not all UV-filters are created equal. Chemical filters have been under the radar of the Environmental Working Group after scientific studies revealed – among other things - hormone disruption effects, photo-oxidative stress and - in some cases - skin cancer! [1, 3-5].In 2008, the Scientific Committee on Consumer Products (SCCP) declared not advisable to apply chemical sunscreens [oxybenzone, avobenzone] before the age of 2. A few years later, several chemical UV-filters were detected in 85% of Swiss breast milk samples [2]. From then, it was not recommended to wear chemical sunscreen while breastfeeding either. And guess what? That same study, detected oxybenzone in 96% of urine samples in the US, meaning ingredients contained in sunscreen enter the bloodstream via the skin. If that wasn’t enough, recent research also revealed that oxybenzone and its relatives [octinoxate, octocrylen, avobenzone] continue their destructive path on marine life and corals down the drain (read more in my next blog).

With oxybenzone and other chemical filters present in over 97% of sunscreens and cosmetics on the market, does that mean we should give up on sun protection and increase risks of sunburns, photo-aging or even skin cancer?​Fortunately, we have a good alternative in the minerals UV-filters zinc oxide and titanium dioxide. Also called physical, these filters are photo-stable and, unlike chemical filters, they have the advantage of blocking both UVA and UVB rays, providing broad-spectrum protection (although titanium dioxide doesn’t protect against the whole range of UVA rays). It is important to note that mineral filters are sometimes used in the form of nanoparticles (ultrafine particles ranging from 1 nm to 100 nm). Research shows that nanoparticles are potentially hazardous under UV illumination, creating a wide range of toxic effects in various environments [6, 7]. So, carefully read the tag and prefer non-nano when it comes to mineral filters.

If you are looking for a clean sunblock, non-nano zinc oxide and titanium dioxide are the way to go, with zinc oxide being most efficient at reflecting the full range of UVs. But keep in mind that it is not all about sunscreen! Wear a hat, protective clothing, and try to avoid prolonged sun exposure between 11am and 3pm. If you haven’t been in the sun recently, try to gradually build your tan. And remember, the Sun created life on Earth and has many health and mental benefits like the secretion of Vitamin D and serotonin (the good mood hormone) in the body.